1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method for uplink transmission in an OFDM(A) wireless communication system.
2. Discussion of the Related Art
A current IEEE 802.16e system uses a tile and pilot structure as shown in FIG. 1 as an uplink Partial Usage of SubChannel (PUSC) structure. One transmit antenna is considered in the structure of FIG. 1. This uplink PUSC basic unit structure has a pilot overhead of 33.33%. In FIG. 1, the pilot and data subcarriers refer to resource elements (REs) allocated for pilot and data respectively. Each RE represents a time-frequency resource defined by one OFDM(A) symbol and one subcarrier. In the following description, the terms “pilot subcarrier” and “data subcarrier” can be interchanged with the terms “pilot RE” and “data RE” respectively.
Since only one transmit antenna is considered in the uplink tile structure used in the current IEEE 802.16e system, the uplink PUSC basic unit structure has a pilot overhead of 33.33%. Thus, the ratio of pilot overhead to data is significant. Such pilot overhead reduces link throughput, causing a reduction in system performance. When an extended basic unit is employed as in IEEE 802.16m, one issue is to reduce pilot overhead.